1. Field
The invention is in the field of methods and apparatus for checking operation of the power propulsion systems of vehicles that are powered by electric traction motors, especially diesel electric and all-electric railway locomotives.
2. State of the Art
It is common railway practice to couple several individual diesel electric or all-electric locomotives together in series to collectively form a single propulsion unit (often referred to merely as "the locomotive"), which is controlled by an engineer in the cab of the leading locomotive of the series.
While each individual locomotive has instrumentation for monitoring certain operating variables of its power propulsion system, it is very difficult for the engineer in the cab of the lead locomotive to determine whether all locomotives are operating properly. There are many instances in which one locomotive is not operating correctly or not at all, which means that that locomotive is being pulled along with the train as dead weight. This increases the work done and fuel consumed by the remaining locomotives. Furthermore, the defective locomotive may remain in service for some time, until a periodic physical check of the equipment shows that there is trouble.
Although several on-board instrumentation systems have been suggested heretofore to monitor the operation of a locomotive's propulsion system during travel, a separate system of this type must be individually installed in each locomotive of a propulsion unit and must be monitored accordingly.
Applicant is aware of only one proposal for analyzing performance of the propulsion system of a locomotive at a stationary location as the locomotive travels past that location, without requiring special equipment to be installed in the locomotive. That is as described in U.S. Pat. No. 3,445,648, and employs heat sensors to sense the temperature of various components of the locomotive as it passes by.
The temperature of exhaust gases from a locomotive and the temperature of the traction motors thereof provide some useful information as to performance, but there is much information of a more useful nature that is not provided by temperature readings.
While heavy automotive vehicles used in road construction and in mining often have traction motors powered by electricity generated by internal combustion engines, applicant is unaware of any attempt to check performance of the power propulsion systems of such vehicles by stationary, roadside instrumentation.